Xenia of St. Petersburg (Russian: Святая блаженная Ксения Петербургская, born as Xenia Grigoryevna Petrova (Russian: Ксения Григорьевна Петрова), c. 1719–1730 – c. 1803) is a patron saint of St. Petersburg, who according to tradition, gave all her possessions to the poor after her husband died.

After his death, Xenia became a "fool-for-Christ" and for 45 years wandered around the streets of St. Petersburg, usually wearing her late husband's military uniform.

In July 2020, the Holy Synod of the Romanian Orthodox Church also resolved to include Xenia of St. Petersburg in its calendar on January 24.

[1] As a saint, she is noted for her intercessions in helping those with employment, marriage, the homeless, for fires, for missing children, and for a spouse.

[3] Xenia is a major figure in the historical fiction novel The Mirrored World by Debra Dean.